1. Field of the Invention
This invention relates to a gas carburizing furnace, and, more particularly, to an improvement of a drip-fed type gas carburizing furnace.
2. Description of the Prior Art
It is a well-known method for carburizing or carbonitriding steels to supply liquid organic composition directly to the atmosphere of the furnace. One example of such a method comprises the steps of preparing a liquid organic composition to generate the raw material gases, said composition having a carbon oxygen atomic ratio (C/O) of 1.5 to 3.0, detecting the equilibrium carbon concentration of the steel surface in the carburizing atmosphere by means of a specially prepared alloyed wire, and automatically controlling the inflow of the liquid organic composition thereby gas carburizing or gas carbonitriding steels in an atmospheric furnace in which the equilibrium carbon concentration of the steel surface is automatically maintained at a desired level. The Applicant has filed a patent application in Japan (Ser. No. 66-77756) in connection with the above-stated method as well as the device to control the carbon concentration and a device to control the inflow rate of the carburizing mixture. While this method and device provides may advantages regarding the automatic control system over the prior art methods, there remains some unsolved problems. First, it is likely that the method suffers from insufficient thermal cracking of the organic composition. Secondly, an undesirable amount of soot may occur during the carburizing operation.